Preheater



Patented June 12, 1934 PATENT OFFICE PREHEATER George L. E. Emmich, Cincinnati, Ohio Application April 9. 1932, Serial No. 604,278

2 Claims.

This is a device which is designed to economize in the use of fuel by raising the temperature of water or other fluids before they are subjected directly to the heating eifects of the fuel employed to bring them to the desired temperature. I am aware that there have been many devices employed for such general purposes. as I have just set forth, and that such devices operate upon the general principle of utilizing the heat of waste or discharge fluids, gases or vaporswhich have been heated directly by the use of the fuel which has been consumed.

In such industrial enterprises as laundries,

where great quantities of wash and rinse water 5 are employed, and where great quantities of fuel are used to bring this water to a high temperature, much economy of operation in the saving of a large part of the fuel costs may be effectedby extracting as much of the heat of the waste wash and rinse water as possible and utilizing this retrievedheat in preheating the fresh water before it passes into the boiler or water heater employed to bring this water to the required temperature for use in the washing and rinsing operations.

In my invention I have a preheater in which an object is to create greater efficiency than has been accomplished in the use of other heaters known to me.

A further object is to produce a preheater which is less subject to leakage troubles created by relative expansion and contraction of the parts thereof in the course of its operation.

A further object is to produce a preheater in which repairs may be accomplished ina minimum length of time and without totally incapacitating the preheater during the period necessary to accomplish such repairs.

These and other objects are attained in the preheater described in the following specification and illustrated in the accompanying drawings, in which;

Fig. 1 is a sectional plan view showing my improved heater and taken on the line 1-1 of Fig. 2.

Fig. 2 is a transverse sectional view taken on the line 2-2 of Fig. 1.

Fig. 3 is a vertical sectional view taken on the line 3'--3 of Fig. 2.

Fig. 4 is an enlarged sectional view taken on the line 4-4 of Fig. 1.

Fig. 5 is an enlarged sectional detail view taken an the line 5-5 of Fig. 1.

Fig. 6 is an enlarged sectional detail view taken on the line 6-6 of Fig. 5.

My improved preheater consists of two principal elements. One of these elements is a tank or well 11 and the other is a heater unit 12 which occupies the tank. The tank may be made of concrete or metal and may be placed in the ground or may be located above the ground as best suits the conditions encountered in the location where the preheater is to be used.

In the illustrated disclosure of my invention I have shown a concrete tank which is best adapted to a location in the ground. This tank has an inlet 13 and an outlet 14, the mouth of the inlet being especially shaped for the purpose for which it is to be used. The mouth 15 of inlet 13 is spreading or flared to take care of the flow of heated waste fluid to the preheater, by providing for its proper distribution throughout the entire width of the tank. This is accomplished by placing the bottom 16 of the mouth so that it is humped or elevated at its center as shown at 1'? in Fig. 5, in order that waste water from inlet 7 13 will be diverted in its passage over the hump to distribute quite uniformly from side to side of the mouth and extend throughout the entire width of the tank.

In the outlet 14 of the tank I have provided a pipe 18 which arises to near the floor surface 19 so that all outgoing waste water will be directed upwardly, thus maintaining a proper level in the tank 11. At the bottom of the tank a drain 20 is provided with a valve 21 so that all sediment may be removed and the tank cleaned, as well as to render the preheater accessible for repairs or inspection. In view of the fact that outlet 14 will, in all probability, lead the overflow into a sewer, it is advisable to provide a cover 22 which will also increase the safety of the apparatus, especially as regards the danger of falling into the tank as well as the chance of sewer gas entering the building in which the tank is located. In the event of the latter danger I have shown the tank equipped with a vent 23 so that accumulation of sewer gas will be prevented. r

The heating unit 12 which occupies the tank, comprises a series of sections 24. Each of these sections is substantially identical and is made so that they may be fastened consecutively to each other in order that progressive circulation through them may be obtained. Any number of sections may thus be connected together up to the point where maximum efiiciency is established. The construction of each section of the preheater being substantially identical, Figs. 1, 2 and 4 will disclose the features thereof as now described. Each section is of piping which is a series of heating coils 25 connected together by means of a header 26 at their upper ends and another header 27 at their lower ends. Each of the headers of each section, is of relatively large pipe and the headers are formed to be fastened together consecutively as shown. The coils 25 are of relatively small size pipe in order that the volume of water through the headers may be distributed uniformly through them. The bottom header 27 is connected with water inlet pipe 28, while the top header 26 is connected with outlet pipe 30. These connections are so that progressive zig-zag flow may be established through the heating unit. The flow of waste water between and around the heating coils operates to a great degree of eiiiciency by taking place as indicated by arrows as shown in Fig. 2, and thence outwardly through outlet 14 and pipe 18.

To permit of expansion and contraction of the preheater sections, it will be observed upon referring to Figs. 2 and 4, that the pipes 25 are all curved or coiled. This is done primarily as a safe guard against possible breakage of pipe joints in the event of excessive or unequal expansion, as may be likely to occur when waste water which contains much easily deposited matte" is used. Thus, a series of coiled or curved pipes 25 will bend slightly under expansion, without causing the pipe joints to open.

In laundry work much accumulation of lint, threads, soap and dirt on the preheater surfaces would materially affect its efiiciency, hence, I have chosen to construct this element in a manner such that there are no sharp or rough corners, edges, pro'ections, lugs, ledges or surfaces which will catch these suspended portions or waste matter. For this reason I have formed all pipe joints and all joints between the pipes and webs, in a smoothly brazed, soldered or sweated manner so that there is found a total elimination of pipe thread surfaces and burrs such as would be created through the use of pipe wrenches on the pipes and couplings in building the sections of the unit. To enhance the value of such construction I choose to employ such smooth and non-corrosive material as brass and copper, which has the additional value that such materials are far more efficient in the transmisslon of heat than wrought iron, cast iron or galvanized pipe and couplings.

I have added a detail of convenience in the construction disclosed. This consists in providing for the removal of any chance accumulations of thread or lint from the coils or sections 24. For this purpose I have provided spray headers 31, such as shown in Figs. 1 and 3, so that the coils 25 of sections 24 may be blown free of accumulations by steam, water or air applied to the headers through pipes 32 connected with the respective headers.

A feature of my invention also lies in the sump 33 which I form in the tank 11, which sump slopes in both directions, as shown in Figs. 2 and 3, toward drain 20, thereby aiding in clearing the tank of all washings and foreign matter removed in the cleaning operation. Another feature lies in the advantage the sump has in allowing cooled waste water to fall rapidly away from the heating unit, thereby also aiding materially in efficiency increase.

The use of my improved preheater is substantially self evident, but it may be that a brief description of its use will be of benefit in certain particulars. In Figs. 1 and 2 there are found arrows from inlet 13 showing how circulation of hot waste water through the channels surrounding the preheater sections, takes place, other arrows showing how cold waste water falls directly to the bottom of the tank without contacting the heating unit. In this circulation some of the waste water which enters the tank through inlet 13 is quite hot. Much fuel has to be used to raise the temperature of water, so that the temperature of this water is slightly under the boiling point. This water after it is used in either washing or rinsing operations, is drained from the washer at a temperature little below that at which it entered the washer, hence, there is a great waste of heat which has been obtained at a cost which has to be figured closely in rendering the operation of a commercial laundry profitable. This is largely saved, by passing the feed water for the water heater of the plant through the preheater unit, preferably in a direction somewhat the reverse of that taken by the waste water through the tank. This is indicated in Fig. 2 by the arrows showing the entrance of such feed water at 28 and its exit at 29. In this manner the cool feed water enters the unit 12 at a point where the waste water is at its coolest, but, nevertheless, warm enough to cause the entering feed water to be heated appreciably.

As the warmer feed water advances, it encounters L pipe surfaces heated by warmer waste water, until, as it enters the last preheater section, its temperature is raised by the walls of this section, to approximate the temperature of the incoming waste water. From this last section it then leaves for entrance to the water heater which supplies the washer, at a temperature markedly increased over that at which it would have entered the heater had it gone directly to the heater instead of through the preheater. In this manner far less fuel is required to complete the heating of the wash'and rinse water, thereby effecting a material saving in cost, although there is also the element of time saving involved in having to wait until the water has arrived at the proper temperature for use in the washer, as well as in being able to. permit of the use of a materially smaller boiler or heater than would be required otherwise.

Having thus described my invention what I claim is:

1. A preheater comprising a tank provided with a sump and having an inlet and an outlet to establish a flow of heated waste liquid across the tank, the mouth of the inlet being opposite the a sump and flared to distribute liquid horizontally from wa'l to wall of the tank, the outlet being in the sump to collect the heated waste liquid after its flow across the tank, and a preheater unit withn the tank, said unit consisting of a series of coiled pipe sections, each' constituting a baflie, the sections being connected together to create a circuitous flow of liquid therebetween, and contrary to the flow through the pipes.

2. A preheater comprising a'tank provided with 1 a sump and having an inlet and an outlet in opposite walls thereof to establish a flow of heated waste liquid across the tank, the mouth of the inlet being opposite the sump, being flared, and

having its bottom humped to effect uniformity of liquid distribution from side to. side of the mouth and tank.

GEORGE L. E. EMMICH. 

